Being a one owner car, the seller likely thinks that it should fall into the survivor / unrestored category. Maybe it is being compared to one of those? This is appears to be a one owner, nice driver, that has had minor sprucing up, with hail damage, and a vinyl top with a seam down the middle?
I am with Neil on value. A painless dent guy will not be able to get all of those dents ironed out. Hail damage is expensive to repair from a labor/time stand point. Potentially worth more with an inspection.
"no visible evidence of rust on the body. There is surface rust on the under-carriage, i.e., frame (please see photographs)."
I do not see any pictures of the under-carriage.